1. Field of the Invention
This invention lies in the field of the attachment of flanges, the term flanges being understood to mean load-bearing terminations attached to other members and having a lateral area larger than the members to which they are attached. More particularly, the present invention deals with methods and means for attaching such flanges to three-dimensional frameworks which are also called major modular assembly jigs, the word "major" implying a structure of some size while "modular" is intended to connote that two or more jigs are to be assembled to make a complete tooling and assembly jig. As illustrated, the overall assembly of modules (plus some additional members) provides working platforms and reference points and plates for the assembly and tool operation upon such large structures as spacecraft, aircraft, sea-going vessels and rail cars.
2. Description of the Prior Art
The only relevant prior art known to the applicant are three-dimensional modules generally similar to those discussed herein, wherein the flanges are attached by welding. These all-welded structures have the usual disadvantages usually associated with welding, e.g., lack of accurate dimensioning, lack of needed co-planarity and lack of needed parallelism. It is difficult to stack one such module on top of another, because pre-drilled holes do not align properly, and adjustments must be made. Also, one set of flanges will not lie exactly on the other set, so shimming between some pairs of adjacent flanges pads must be resorted to; this may also be true of the bottom set of flanges, which are to support the framework on a floor or other rest, for if shims are not used the structure may deviate considerably from the vertical. Such welded-flange frameworks are highly unsatisfactory for re-use when a second spacecraft is to be put together, as it is generally less frustrating to start from scratch and build a new framework (scrapping the old one).